The present invention relates to an airbag system, a cover component thereof, and a vehicle interior trim. More particularly, it concerns a cover component having an improved tear line, an airbag system including the cover component, and a vehicle interior trim such as an instrument panel.
Cover components for airbag systems mounted to high-speed movable bodies such as automobiles include a folded airbag, a gas supply means for inflating the airbag, and a cover component for covering the folded airbag. The cover component is sometimes referred to as a module cover, a lid, a deployment door and so on.
An instrument panel itself in place of the cover component is sometimes provided with a tear line.
The cover component and the instrument panel are manufactured by molding a synthetic resin material with a die. On the surface of the cover component and the instrument panel, leather, felt or the like is sometimes integrally formed.
One type of the cover component and the instrument panel has a tear line (brittle linear part) which is torn open by the pressure of an airbag when the airbag inflates to thereby open the cover component or the instrument panel.
The tear line is generally formed using a raised line provided on the core surface of a die for molding the cover component or the instrument panel. When the core surface has the raised line, a recessed line corresponding to the raised line is formed in the molded cover component. Another method for forming the tear line is described in Japanese Unexamined Patent Application Publication No. 8-282420, in which a recess or a recessed line is formed by exposing a cover component to a laser beam. FIG. 8 of the publication shows a tear line formed of an even-depth recessed line. FIG. 20 of the publication shows a tear line having hollows at intervals in a recessed line. In the publication, both the recessed line and the hollows in FIG. 20 are formed with a laser beam.
When the recessed line and the hollows as in FIG. 20 of the above-mentioned Japanese Unexamined Patent Application Publication No. 8-282420 are formed by a laser processing method by which recesses are formed by exposure to a laser beam, cycle change of laser output is a possible approach. More specifically, an increase in laser output will increase the depth of the recess while a decrease in laser output will decrease the depth of the recess.
However, when the recessed line is formed in a specified depth by laser light as described above, the relative speed between the laser output and the movement of the cover component or the workpiece must be strictly controlled and the time for laser processing is increased.